Comparison of the Load at Fracture of Turkom-Cera to Procera AllCeram and In-Ceram All-Ceramic Restorations

Purpose: This study investigated the occlusal fracture resistance of Turkom-Cera-fused alumina compared to Procera AllCeram and In-Ceram all-ceramic restorations.
Materials and Methods: Six master dies were duplicated from the prepared maxillary first premolar tooth using nonprecious metal alloy (Wiron 99). Ten copings of 0.6 mm thickness were fabricated from each type of ceramic, for a total of thirty copings. Two master dies were used for each group, and each of them was used to lute five copings. All groups were cemented with resin luting cement Panavia F according to manufacturer's instructions and received a static load of 5 kg during cementation. After 24 hours of distilled water storage at 37°C, the copings were vertically compressed using a universal testing machine at a crosshead speed of 1 mm/min.
Results: The results of the present study showed the following mean loads at fracture: Turkom-Cera (2184 ± 164 N), In-Ceram (2042 ± 200 N), and Procera AllCeram (1954 ± 211 N). ANOVA and Scheffe's post hoc test showed that the mean load at fracture of Turkom-Cera was significantly different from Procera AllCeram ( p < 0.05). Scheffe's post hoc test showed no significant difference between the mean load at fracture of Turkom-Cera and In-Ceram or between the mean load at fracture of In-Ceram and Procera AllCeram.
Conclusion: Because Turkom-Cera demonstrated equal to or higher loads at fracture than currently accepted all-ceramic materials, it would seem to be acceptable for fabrication of anterior and posterior ceramic crowns.     

Marginal adaptation and microleakage of Procera AllCeram crowns with four cements

PURPOSE: This study investigated the effect of different cements on microleakage and marginal adaptation of porcelain crowns. MATERIALS AND METHODS: Eighty extracted molars were divided into two groups. Teeth in one group were prepared to receive Procera AllCeram crowns, whereas the other group was prepared to receive metal-ceramic crowns. Copings were made following standard techniques, and groups were divided for cementation with zinc phosphate, glass-ionomer, resin-modified glassionomer, or resin cement. Specimens were subjected to thermocycling prior to microleakage testing, then sectioned. Microleakage was scored using a five-point scale; marginal adaptation was assessed with a traveling microscope. RESULTS: A significant association was found between cement type and degree of microleakage. With zinc phosphate, 76% of Procera AllCeram and 90% of metal-ceramic copings exhibited extensive microleakage. With glass-ionomer, 49% of Procera AllCeram and 66% of metal-ceramic copings had 0 microleakage scores; with resin-modified glass-ionomer, 10% of Procera AllCeram and 84% of metal-ceramic copings had 0 microleakage scores. With resin cement, 34% of Procera AllCeram and 96% of metal-ceramic copings exhibited 0 microleakage. Procera AllCeram copings had a significantly larger mean marginal gap (54 microm) compared to metal ceramic (29 microm). CONCLUSION: In both types of crowns, the use of resin cement resulted in the highest percentage of 0 microleakage scores, whereas the zinc phosphate cement resulted in the highest percentage of extensive microleakage.     

Dentin bonding of cements. The bonding of cements with dentin in combination with various indirect restorative materials

The number of both luting agents and restorative materials available on the market has rapidly increased. This study compared various types of luting agents when used to bond different indirect, laboratory restorative materials to dentin. Cylinders were produced of six restorative materials (gold alloy, titanium, feldspathic porcelain, leucite-glass ceramic, zirconia, and an indirect resin composite). Following relevant pretreatment, the end surface of the cylinders were luted to ground, human dentin with eight different luting agents (DeTrey Zinc [zinc phosphate cement], Fuji I [conventional glass ionomer cement], Fuji Plus [resin-modified glass ionomer cement], Variolink II [conventional etch-and-rinse resin cement], Panavia F2.0 and Multilink [self-etch resin cements], RelyX Unicem Aplicap and Maxcem [self-adhesive resin cements]). After water storage at 37 °C for one week, the shear bond strength of the specimens was measured and the fracture mode was examined stereo-microscopically. Restorative material and luting agent both had a significant effect on bond strength and there was a significant interaction between the two variables. The zinc phosphate cement and the glass ionomer cements resulted in the lowest bond strengths, whereas the highest bond strengths were found with the two self-etch and one of the self-adhesive resin cements.     

Mechanical properties of luting cements after water storage

This study determined the effect of water storage on flexural strength (FS) and compressive strength (CS) of 12 luting cements from different material classes. In addition, the influence of the curing method on the mechanical properties was investigated. The materials examined were two zinc phosphate cements (Harvard cement and Fleck's zinc cement), two glass ionomer cements (Fuji I and Ketac-Cem), three resin-modified glass ionomer cements (Fuji Plus, Fuji Cem and RelyX Luting), four resin cements (RelyX ARC, Panavia F, Variolink II and Compolute) and one self-adhesive universal resin cement (RelyX Unicem). The samples were prepared and tested according to ISO specifications. Specimens for FS and CS were loaded to fracture at a constant crosshead speed of 1 mm/minute. The mechanical properties were measured after the materials were stored in distilled water at a temperature of 37.0 +/- 1.0 degrees C for 24 hours and 150 days after mixing. In a one-way ANOVA, multiple mean value comparisons using Duncan's multiple comparison tests were performed. Resin cements had the highest flexural and compressive strengths, followed by self-adhesive universal resin cement. These materials were statistically stronger than resin-modified glass ionomer cements, glass ionomer cements and zinc phosphate cements.     

Vertical marginal discrepancy of ceramic copings with different ceramic materials, finish lines, and luting agents: an in vitro evaluation

STATEMENT OF PROBLEM: Prosthetic restorations that fit poorly may affect periodontal health and occlusion. Studies that have evaluated the accuracy of fit of ceramic restorations before and after cementation assessed primarily intracoronal restorations. PURPOSE: This in vitro study evaluated the effect of different finish lines, ceramic manufacturing techniques, and luting agents on the vertical discrepancy of ceramic copings. MATERIAL AND METHODS: Two stainless steel molars were prepared for complete crowns with 2 different finish lines (heavy chamfer and rounded shoulder); each molar was duplicated to fabricate 90 copings. A total of 180 copings generated 18 groups (n=10 for each finish line-coping material-luting agent combination). Luting agents tested included zinc phosphate, resin-modified glass ionomer (Fuji Plus), and resin composite cements (Panavia F). A metal frame was developed on which to screw the stainless steel model and a ceramic coping; the distance (microm) between 2 predetermined points was measured before and after cementation by a profile projector under a torquing force. A 4-way ANOVA with repeated measurements was performed to assess the influence of each factor in the vertical marginal discrepancy: 3 between-coping factors (finish line-coping material-luting agent) and 1 within-coping factor (before and after cementation) (alpha=.05). RESULTS: Procera copings presented the lowest mean values ( P <.05) of vertical marginal discrepancy before and after cementation (25/44 microm) when compared to Empress 2 (68/110 microm) and InCeram Alumina copings (57/117 microm), regardless of any combinations among all finish lines and luting agents tested. CONCLUSION: Considering each factor separately, the ceramic manufacturing technique appeared to be the most important factor tested for the definitive vertical discrepancy of all-ceramic copings, with lower mean values for Procera copings.     

Bonding of restorative materials to dentin with various luting agents

The aim was to compare eight types of luting agents when used to bond six indirect, laboratory restorative materials to dentin. Cylinders of the six restorative materials (Esteticor Avenir [gold alloy], Tritan [titanium], NobelRondo [feldspathic porcelain], Finesse All-Ceramic [leucite-glass ceramic], Lava [zirconia], and Sinfony [resin composite]) were ground and air-abraded. Cylinders of feldspathic porcelain and glass ceramic were additionally etched with hydrofluoric acid and were silane-treated. The cylinders were luted to ground human dentin with eight luting agents (DeTrey Zinc [zinc phosphate cement], Fuji I [conventional glass ionomer cement], Fuji Plus [resin-modified glass ionomer cement], Variolink II [conventional etch-and-rinse resin cement], Panavia F2.0 and Multilink [self-etch resin cements], and RelyX Unicem Aplicap and Maxcem [self-adhesive resin cements]). After water storage at 37°C for one week, the shear bond strength of the specimens (n=8/group) was measured, and the fracture mode was stereomicroscopically examined. Bond strength data were analyzed with two-factorial analysis of variance (ANOVA) followed by Newman-Keuls' Multiple Range Test (α=0.05). Both the restorative material and the luting agent had a significant effect on bond strength, and significant interaction was noted between the two variables. Zinc phosphate cement and glass ionomer cements produced the lowest bond strengths, whereas the highest bond strengths were found with the two self-etch and one of the self-adhesive resin cements. Generally, the fracture mode varied markedly with the restorative material. The luting agents had a bigger influence on bond strength between restorative materials and dentin than was seen with the restorative material.     

4种玻璃离子水门汀对ITI基台与金属内冠之间粘接力的比较研究

目的：研究4种玻璃离子类水门汀对ITI种植系统标准颈粘接固位基台和金属内冠之间的粘接力。方法将10只金属内冠与10只I T I标准颈粘接固位基台分别使用以下4种水门汀进行交叉粘固：A组为玻璃离子水门汀（日本）;B组为树脂加强型玻璃离子水门汀（美国）;C组为暂时粘固用玻璃离子水门汀（日本）;D组为玻璃离子水门汀（德国）;粘固后测试并记录样本粘接力（N）,同时观察并记录粘固界面的断裂模式,最后,对粘接力进行统计学处理。所有内冠和基台经清洗后重复使用。结果4种水门汀的粘接力及由大至小的排列顺序为C组（183.6±29.4） N〉D组（153.4±36.2） N〉B组（144.4±41.1） N〉A组（109.9±25.7）N,其中C组的粘接力最高,A组的粘接力最低,A组显著低于其它3种水门汀（P〈0.05）。对样本的断裂面观察显示,A组和D组样本断裂面发生在水门汀和基台表面之间,而B组和C组样本的断裂面则呈现混合断裂的模式。结论2种玻璃离子水门汀和树脂加强型玻璃离子水门汀都具有临床可接受的粘接力,而暂时粘固用玻璃离子水门汀因粘接力太大,不适用对种植牙冠进行暂时粘固。     

In vitro shear bond strength of cementing agents to fixed prosthodontic restorative materials

STATEMENT OF PROBLEM: Durable bonding to fixed prosthodontic restorations is desirable; however, little information is available on the strength of the bond between different cements and fixed prosthodontic restorative materials. PURPOSE: This study determined the shear-bond strength of cementing agents to high-gold-content alloy castings and different dental ceramics: high-strength aluminum oxide (Procera AllCeram), leucite-reinforced (IPS Empress), and lithium disilicate glass-ceramic (IPS Empress 2). MATERIAL AND METHODS: Prepolymerized resin composite cylinders (5.5 mm internal diameter, n=20) were bonded to the pretreated surfaces of prosthodontic materials. High-gold-content alloy and high-strength aluminum oxide surfaces were airborne-particle-abraded, and pressable ceramics were hydrofluoric acid-etched and silanized prior to cementing. The cementing agents tested were a zinc-phosphate cement (Fleck's zinc cement), glass ionomer cements (Fuji I, Ketac-Cem), resin-modified glass ionomer cements (Fuji Plus, Fuji Cem, RelyX Luting), resin cements (RelyX ARC, Panavia F, Variolink II, Compolute), and a self-adhesive universal resin cement (RelyX Unicem). Half the specimens (n=10) were tested after 30 minutes; the other half (n=10) were stored in distilled water at 37 degrees C for 14 days and then thermal cycled 1000 times between 5 degrees C and 55 degrees C prior to testing. Shear-bond strength tests were performed using a universal testing machine at a constant crosshead speed of 0.5 mm/min. Statistical analysis was performed by multifactorial analysis of variance taking interactions between effects into account. For multiple paired comparisons, the Tukey method was used (alpha=.05). RESULTS: In a 3-way ANOVA model, the main factors substrate, cement, time, and all corresponding interactions were statistically significant (all P <.0001). In subsequent separate 1-way or 2-way ANOVA models for each substrate type, significant differences between cement types and polymerizing modes were found (all P <.001). None of the cement types provided the highest bonding values with all substrate types. CONCLUSION: After 14 days of water storage followed by thermal cycling, only the self-adhesive universal resin cement (RelyX Unicem) and 2 of the resin cements (Panavia F and Compolute) exhibited strong bond strengths to specific prosthodontic materials. In contrast, zinc-phosphate, glass ionomer, and resin-modified glass ionomer cements showed the lowest values of all tested cementing agents after 14 days of water storage followed by thermal cycling.     

Resistance to Fracture of Three All-Ceramic Systems

Abstract: All-ceramic restorations have become an attractive alternative to porcelain-fused-to-metal crowns, but their strength is still an important issue. The purpose of this study was to compare the in vitro fracture resistance of three all-ceramic systems: IPS Empress, In-Ceram, and Procera AllCeram. Thirty dies were replicated from a master die using high filler resin with a modulus of elasticity similar to dentin. Ten cores each of In-Ceram and Procera were fabricated to a thickness of 0.5 mm. The remaining porcelain was applied using a sculpting device to produce a crown with a final thickness of 1.0 mm axially and 2.5 mm occlusally. Ten IPS Empress crowns were waxed to the same dimensions and were pressed by the manufacturer. The internal surfaces of all the crowns were etched and silanated prior to cementation with a resin cement (Panavia 21). The cemented samples were loaded in an Instron machine until fracture. The mean fracture loads were: IPS Empress, 222.45 (±49) kg; In-Ceram, 218.8 (±36) kg; Procera AllCeram, 194.20 (±37) kg. Tukey's test showed no statistically significant differences among the three all-ceramic systems at p < .05.     

Use of zinc phosphate cement as a luting agent for Denzir trade mark copings: an in vitro study

BACKGROUND: The clinical success rate with zinc phosphate cemented Procera crowns is high. The objective with this study was to determine whether CADCAM processed and zinc phosphate cemented Denzir copings would perform as well as zinc phosphate cemented Procera copings when tested in vitro in tension. METHODS: Twelve Procera copings and twenty-four Denzir copings were made. After the copings had been made, twelve of the Denzir copings were sandblasted on their internal surfaces. All copings were then cemented with zinc phosphate cement to carbon steel dies and transferred to water or artificial saliva. Two weeks after cementation, half of the samples were tested. The remaining samples were tested after one year in the storage medium. All tests were done in tension and evaluated with an ANOVA. RESULTS: Sandblasted and un-sandblasted Denzir copings performed as well as Procera copings. Storage in water or artificial saliva up to one year did not decrease the force needed to dislodge any of the coping groups. Three copings fractured during testing and one coping developed a crack during testing. The three complete fractures occurred in Procera copings, while the partly cracked coping was a Denzir coping. CONCLUSION: No significant differences existed between the different material groups, and the retentive force increased rather than decreased with time. Fewer fractures occurred in Denzir copings, explained by the higher fracture toughness of the Denzir material. Based on good clinical results with zinc phosphate cemented Procera crowns, we foresee that zinc phosphate cement luted Denzir copings are likely to perform well clinically.     

An in vitro study to investigate the load at fracture of Procera AllCeram crowns with various thickness of occlusal veneer porcelain

PURPOSE: The aim of this study was to investigate the effect of occlusal veneer porcelain thickness on the load at fracture of Procera AllCeram crowns. MATERIALS AND METHODS: Fifty resin dies were manufactured to incorporate the features of an all-ceramic crown preparation on a premolar tooth. Fifty corresponding crowns were constructed and divided into five groups. Groups 1, 2, 3, and 4 were crowns with 0.6-mm-thick Procera cores and 0.4-mm-thick axial veneer porcelain and occlusal veneer porcelain thicknesses of 0.0 mm, 0.4 mm, 0.9 mm, and 1.4 mm, respectively. Group 5 specimens consisted of 0.6-mm-thick In-Ceram cores with 0.4 mm of axial porcelain and 0.4 mm of occlusal porcelain. The crowns were cemented onto their respective dies with a resin luting agent. Specimens were stored in distilled water at 37 degrees C for 24 hours prior to placing them in a universal testing machine and applying a controlled compressive load at a cross-head speed of 0.1 mm/min until fracture occurred. RESULTS: The mean loads at fracture were 419 N (group 1), 702 N (group 2), 1,142 N (group 3), 1,297 N (group 4), and 732 N (group 5). Statistical analysis revealed significant differences (P < .05) in the load at fracture between the groups, except for between groups 2 and 5. CONCLUSION: Increasing the thickness of the occlusal veneer porcelain increased the load at fracture for Procera AllCeram crowns. There was no significant difference in load at fracture between the Procera and In-Ceram crowns.     

In vitro evaluation of long-term bonding of Procera AllCeram alumina restorations with a modified resin luting agent

STATEMENT OF PROBLEM: Bonded densely sintered aluminum oxide ceramic restorations such as Procera AllCeram laminates rely on a strong and long-term durable resin bond. Air particle abrasion and a phosphate-modified resin luting agent have the potential to provide such bonds to aluminum oxide ceramics, but their efficacy on the Procera AllCeram intaglio surface is unknown. The inherent microroughness of this surface may influence bond strengths, because micromechanical interlocking is a main contributor for adhesion of resins to ceramic materials. PURPOSE: This study evaluated the bond strength of a phosphate-modified resin luting agent with and without silanization to an air particle-abraded Procera AllCeram intaglio surface compared with a conventional resin-bonding system before and after artificial aging. MATERIAL AND METHODS: Sixty square (10 x 10 x 2 mm) specimens of Procera AllCeram alumina ceramic with the Procera intaglio surface were air particle abraded with aluminum oxide. Composite cylinders (2.9 mm in diameter and 3.0 mm in width) were fabricated with Z-250 composite and bonded to the ceramic specimens with either Panavia 21 TC or Rely X ARC (control) and their corresponding bonding/silane coupling agents. In addition, Panavia was used without silanization as suggested in similar studies. Subgroups of 10 specimens were stored in distilled water for either 3 or 180 days before shear bond strength was tested with a universal testing machine (MPa) until fracture. The 180-day specimens were subjected to thermocycling at 2000 cycles every 30 days (12,000 cycles total). Data were analyzed with 1-way analysis of variance and Tukey's multiple comparison (alpha=.05). Failure modes were examined with a light microscope (original magnification x 25). RESULTS: Differences between short-term and long-term groups were highly significant (P=.000). Bond strength with Rely X ARC and its silane coupling agent (22.75 +/- 4 MPa) decreased significantly (P=.000) after artificial aging (3.32 +/- 3.62 MPa). Panavia 21 after silanization revealed significantly different (P=.003) early (21.42 +/- 4.3 MPa) and late (16.09 +/- 2.37 MPa) bond strengths but achieved the highest bond strength after artificial aging. Bond strengths of Panavia without silanization both early (8.06 +/- 2.1 MPa) and late (6.91 +/- 2.49 MPa) were not significantly different. Failure modes were mainly adhesive at the ceramic surface for all groups. CONCLUSION: Panavia 21 in combination with its corresponding bonding/silane coupling agent can achieve an acceptable resin bond to the air particle-abraded intaglio surface of Procera AllCeram restorations after artificial aging, which had mixed effects on the other investigated groups. The conventional resin luting agent revealed the most dramatic decrease in bond strength.     

Demineralization resistance and tensile bond strength of four luting agents after acid attack

Resistance to acid demineralization provided by luting agents adjacent to enamel was evaluated for four different luting agents: composite resin, glass ionomer, polycarboxylate, and zinc phosphate cement. Cement solubility and enamel demineralization after acid attack at pH 3.0 were measured radiographically and calculated using computer-aided design. Tensile bond strength of a miniature crown seated on an accurately prepared preparation was evaluated after acid attack using an Instron instrument. Crown retention after 12 days was greater for the polycarboxylate (2,000 kg/m2) than the zinc phosphate cement (500 kg/m2). Crown retention for the glass ionomer (1,100 kg/m2) and composite resin luting agent (1,400 kg/m2) were similar statistically after 21 days of acid exposure. Cement washouts for zinc phosphate and polycarboxylate were similar, and were greater than either glass ionomer or composite resin luting agent. The amount of demineralization related to cements was, from greatest to least: zinc phosphate, polycarboxylate, composite resin, glass ionomer. Fluoride release was concluded to be initially effective in reducing enamel solubility in spite of cement solubility.     

Clinical Evaluation of 209 All‐Ceramic Single Crowns Cemented on Natural and Implant‐Supported Abutments with Different Luting Agents: A 6‐Year Retrospective Study

Background: The Procera AllCeram? system (Nobel Biocare AB, Göteborg, Sweden) is a valid alternative to metal–ceramic restorations. However, limited long‐term data of its use for single crowns on natural and implant‐supported abutments are available. Purpose: The present study aimed at evaluating the clinical performances of Procera AllCeram single crowns in both anterior and posterior regions of the oral cavity either on natural tooth or implant abutments over a period of 6 years. Materials and Methods: Two hundred nine single crowns were fabricated and used in 112 patients. Zinc phosphate and resin luting agents were used to cement the restorations. The crowns were evaluated according to the California Dental Association's quality assessment system. Results: Three crowns were lost at follow‐up. Of the 206 restorations, which completed the 6‐year follow‐up, 9 crowns were affected by mechanical complications and 7 crowns failed. All surviving crowns were ranked as either excellent or acceptable. Cumulative survival and success rates of 95.2 and 90.9%, respectively, were recorded. Conclusions: Within the limitations of the present study, Procera AllCeram crowns proved to be a reliable clinical option to restore both anterior and posterior missing teeth either on natural or implant abutments. The resin cement used in the present study performed better than the zinc phosphate luting agent.     

Retrievability of implant‐retained crowns following cementation

Objectives: The purpose of this study was to assess the retrievability of cemented implant crowns using two different removal devices. The influence of five cement types and two cement application techniques was evaluated. Methods: Forty copings were cast from a CoCr alloy for 40 tapered titanium abutments (5° taper, 4.3 mm diameter, 6 mm height, Camlog, Germany). Twenty copings were modeled as single crowns, whereas 20 copings were modeled with an extension to simulate fixed partial dentures (FPDs). Before cementation, the inner surfaces of the copings were air‐abraded (50 μm Al₂O₃ particles at 2.5 bars), while the abutments were used as delivered with machined surfaces. Copings were cemented with eugenol‐free zinc oxide (Freegenol), zinc phosphate (Harvard), glass ionomer (Ketac Cem), polycarboxylate (Durelon) and so‐called self‐adhesive resin (RelyX Unicem) cement. Cement was applied in a thin film band of 1 or 3 mm to the cervical margin of the inner surface of the copings, respectively. After cementation, specimens were stored in saline solution for 24 h. The Coronaflex and a standardized custom‐made removal device were used to remove the copings from the abutments. Results: Using the same cement, no statistically significant influence with regard to the type of restoration (crown/FDP), cement application mode and device was detected (P>0.05). Therefore, data of specimens cemented with the same cement were pooled. Median attempts to remove the copings were: zinc oxide: 3, self‐adhesive resin: 3, zinc phosphate: 5, glass ionomer: 16 and polycarboxylate: 58. Four levels of significance (P<0.0001) were found: (1) zinc oxide/self‐adhesive resin; (2) zinc phosphate; (3) glass ionomer; and (4) polycarboxylate. Conclusions: Zinc phosphate and glass ionomer cement might be suitable for a so‐called ‘semipermanent’ (=retrievable) cementation, while polycarboxylate seems to provide the most durable cementation.     

In‐vitro solubility of three types of resin and conventional luting cements

The solubility of resin luting cement remains unknown although the use of resin luting cement for routine cementation of restorations has increased. The purpose of this in‐vitro study was to compare the solubilities of three resin cements currently in clinical use with three brands of conventional luting agents. The three resin luting cements, All‐Bond C&B^® (AB, Bisco) Panavia 21^® (P21, Kuraray), and Super‐Bond C&B^® (SB, Sun‐Medical), and the three conventional luting agents, Elite Cement 100^® (EC, zinc phosphate cement, GC), HY‐Bond Carbo‐plus Cement^® (HCP, polycarboxylate cement, Shofu), and Fuji I^® (FI, glass‐ionomer cement, GC) were used in this study. A modification of the ADA specification test was adopted to evaluate the solubilities of luting cements. The two types of media (distilled water and pH 4·0 lactic acid solution) in which specimens were stored for 30 days were prepared. The four luting cements, EC, FI, AB, and P21, were more soluble in lactic acid solution than in distilled water. Resin luting cements were markedly less soluble than conventional luting agents when placed in fresh lactic acid solution (0·001 mol/L) at pH 4·0 every 24 h over a 30‐day period. The solubility rates of luting cements could be fitted to mathematical expressions which indicated that the solubilities increased linearly or logarithmically with immersion period. Fixed prosthodontic restorations cemented with resin luting cement may be capable of withstanding long‐term clinical use compared with conventional luting agents.     

The effect of silica coating on the resin bond to the intaglio surface of Procera AllCeram restorations.

OBJECTIVES: This study investigated the influence of a silica-coating method on the resin bond of two different resin composite cements to the intaglio surface of Procera AllCeram densely sintered, high-purity, alumina ceramic restorations after long-term storage and thermocycling. METHOD AND MATERIALS: Densely sintered alumina ceramic specimens were fabricated with the intaglio surface of the Procera AlICeram coping and randomly divided into five adhesive groups (100 total specimens). Resin composite cylinders were bonded either to the untreated or to the tribochemical silica/silane-coated ceramic surface with either a conventional Bis-GMA resin cement or a resin composite containing an adhesive phosphate monomer (Panavia 21) in combination with their corresponding bonding/silane coupling agents. Panavia was also used without silanization to the untreated ceramic surface (control). Subgroups of 10 specimens were stored in distilled water for either 3 (baseline) or 180 days prior to shear bond strength testing. The 180-day samples were subjected to repeated thermocycling for a total of 12,000 cycles. Data were analyzed with one-way analysis of variance and Tukey's multiple comparison. RESULTS: Silica coating significantly increased overall bond strength to Procera AllCeram. RelyX ARC and silica coating revealed the highest bond strength at baseline. Long-term storage and thermocycling significantly decreased overall bond strength. Two groups revealed the significantly highest bond strength values after artificial aging: Panavia 21 with its silane/bonding agent to the original ceramic surface and Panavia 21 to the silica-coated ceramic surface. CONCLUSION: The use of a resin composite containing an adhesive phosphate monomer either in combination with a silane coupling/bonding agent or after tribochemical silica/silane coating revealed the highest long-term shear bond strength to the intaglio surface of Procera AllCeram restorations.     

Fracture toughness of resin-based luting cements

STATEMENT OF PROBLEM. The introduction of resin-modified glass ionomer cements has expanded the choices of luting cements available to the clinician; however, few independent studies are available on the fracture toughness of the currently available resin-modified glass ionomer luting agents compared with the composite cements. PURPOSE. This investigation evaluated the relative fracture toughness (K(IC)) of 3 composite luting cements (Panavia 21, Enforce, and C&B Metabond), 3 resin-modified glass ionomer luting cements (Advance, Vitremer Luting, and Fuji Duet), and a conventional glass ionomer luting cement (Ketac-Cem) at 24-hour and 7-day storage times. MATERIAL AND METHODS. K(IC) was determined by preparing minicompact test specimens (n = 8) with introduced precracks. Specimens were stored in distilled water at 37 degrees C + 2 degrees C until testing. Testing was performed on an Instron testing machine at a displacement rate of 0.5 mm/min. RESULTS. ANOVA (P <.001) and REGW Multiple Range Test (P <.05) demonstrated significant differences among several of the cements tested. The mean fracture toughness values of C&B Metabond at 24 hours and Enforce at both 24 hours and 7 days were significantly greater than use any of the other cements tested. CONCLUSION. The resin-modified glass ionomer cements exhibited improved fracture toughness when compared with the conventional glass ionomer; however, they were still inferior to Enforce and C&B Metabond composite cements.     

Influence of types and surface treatment of dental alloy and film thickness of cements on bond strength of dental luting cements

The goal of this study was to test the influence of the type and oxidation treatment of dental casting alloys on the tensile bond strength of luting cements. Also, the influence of film thickness of luting cements on the tensile bond strength of different dental casting alloys was examined. Four different luting cements (zinc phosphate, polycarboxylate, glass ionomer and adhesive resin cements) and four different dental casting alloys (Au-Ag-Cu, Ag-Pd, hardened Ag-Pd and Ni-Cr alloys) were used. Cylindrical alloy rods for the tensile bond strength test were casted, and then, top surfaces of the rods were cemented with each luting cement to the bottom surfaces of other rods, using the film thickness adjustment apparatus. The film thickness of luting cement was adjusted to 20, 30, 50, 75 or 100 microns. The tensile bond strengths of each cement to different casting alloys at each film thickness were measured one day after the rods had been cemented. The tensile bond strength of the zinc phosphate cement could not be determined in this study due to the separation of the alloy rods cemented with the zinc phosphate cement in water before the tensile test. The tensile bond strength to the adhesive resin cement to any alloy showed the greatest strength; however, that of the glass ionomer cement to any alloy was the lowest strength among the cements examined. The Ni-Cr alloy had the highest bond strength of any luting cement, compared to other alloys. The tensile bond strengths of luting cements significantly decreased with the increase in film thickness of cement layer. The adhesive resin cement had the greatest bond strength, and the glass ionomer cement was the lowest bond strength at any film thickness. The oxidation treatment significantly increased the bond strength of the adhesive resin cement to both Au-Ag-Cu and Ag-Pd alloys. The tensile bond strength of the adhesive resin cement was most dependent upon the film thickness of cement layer, and that of the polycarboxylate cement was least dependent upon the film thickness of cement layer among the cements examined. In addition, the oxidation treatment for precious alloys could be a factor contributing to the increase in the bond strength of the adhesive resin cement.     

四种修复粘接材料的体外细胞毒性研究

目的 比较4种修复粘接材料—聚羧酸锌水门汀、玻璃离子水门汀( FujiI)、树脂改性玻璃离子水门汀( RelyXTM Luting)、树脂类粘接剂(Super-Bond C&B)对人牙髓细胞的生物学作用.方法 原代培养人牙髓细胞,同时制备各材料样品,浸入α-MEM培养基制取材料浸提液.分别将各材料的浸提液与第4代人牙髓...